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// Copyright (c) 2010 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include <functional>
#include "base/logging.h"
#include "remoting/base/multiple_array_input_stream.h"
namespace remoting {
MultipleArrayInputStream::MultipleArrayInputStream(int count)
: buffer_count_(count),
current_buffer_(0),
current_buffer_offset_(0),
position_(0),
last_returned_size_(0) {
DCHECK_GT(buffer_count_, 0);
buffers_.reset(new const uint8*[buffer_count_]);
buffer_sizes_.reset(new int[buffer_count_]);
}
MultipleArrayInputStream::~MultipleArrayInputStream() {
}
bool MultipleArrayInputStream::Next(const void** data, int* size) {
if (current_buffer_ < buffer_count_) {
// Also reply with that is remaining in the current buffer.
last_returned_size_ =
buffer_sizes_[current_buffer_] - current_buffer_offset_;
*data = buffers_[current_buffer_] + current_buffer_offset_;
*size = last_returned_size_;
// After reading the current buffer then advance to the next buffer.
current_buffer_offset_ = 0;
++current_buffer_;
position_ += last_returned_size_;
return true;
}
// We've reached the end of the stream. So reset |last_returned_size_|
// to zero to prevent any backup request.
// This is the same as in ArrayInputStream.
// See google/protobuf/io/zero_copy_stream_impl_lite.cc.
last_returned_size_ = 0;
return false;
}
void MultipleArrayInputStream::BackUp(int count) {
DCHECK_LE(count, last_returned_size_);
DCHECK_EQ(0, current_buffer_offset_);
DCHECK_GT(current_buffer_, 0);
// Rewind one buffer.
--current_buffer_;
current_buffer_offset_ = buffer_sizes_[current_buffer_] - count;
position_ -= count;
DCHECK_GE(current_buffer_offset_, 0);
DCHECK_GE(position_, 0);
}
bool MultipleArrayInputStream::Skip(int count) {
DCHECK_GE(count, 0);
last_returned_size_ = 0;
while (count && current_buffer_ < buffer_count_) {
int read = std::min(
count,
buffer_sizes_[current_buffer_] - current_buffer_offset_);
// Advance the current buffer offset and position.
current_buffer_offset_ += read;
position_ += read;
count -= read;
// If the current buffer is fully read, then advance to the next buffer.
if (current_buffer_offset_ == buffer_sizes_[current_buffer_]) {
++current_buffer_;
current_buffer_offset_ = 0;
}
}
return count == 0;
}
int64 MultipleArrayInputStream::ByteCount() const {
return position_;
}
void MultipleArrayInputStream::SetBuffer(
int n, const uint8* buffer, int size) {
CHECK(n < buffer_count_);
buffers_[n] = buffer;
buffer_sizes_[n] = size;
}
} // namespace remoting
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